In a processing apparatus for manufacturing semiconductor devices such as large scale integrated (LSI) circuits and the like, oxygen concentration in the processing apparatus or in a pod which is transferred into the processing apparatus is reduced in order to suppress formation of natural oxide films on a substrate which is being processed.
However, it is difficult for the processing apparatus configured as above to provide a high quality semiconductor device and high throughput of manufacturing a semiconductor device while suppressing formation of natural oxide films, which are in high demand by recent miniaturizing techniques.